When Worlds Collide
by swordsandstories
Summary: The Doctor has a run-in with Sam, Dean and Cas! This is just a fun little one-shot that I've been dying to write for a long time. I had fun writing it, so I hope you like it too!


**Yaaaay! I'm back! And with a whole new story for you guys! See, I'm not a loser. I did write something!**

**This is mostly dialogue, but I am not sure what else I should include. Maybe I will come back and edit it. Maybe I won't. We'll see. ;) Also, there's a little bit of implied Destiel, just because I couldn't resist. :3 It's a little short, but I kinda like it.  
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**Be prepared for the awesomeness that is Supernatural and Doctor Who... in one place!**

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"You know aliens don't actually exist, right?"

"_Oi_! You're talking to one, buddy. Can we put the gun down now?"

The Doctor was standing about ten feet away from his Tardis, his back against a wall. Three men stood in front of him, and two of them held weapons. The only man without a gun, the one in the trench coat, turned to address the man who was talking.

"Dean," he said, his voice surprisingly gruff, "He may be telling the truth."

"Shut up, Cas," the other man (Dean, the Doctor presumed) muttered back at him.

"But Dean, he has_ two hearts_."

At this statement Dean seemed baffled, and he shared a look with the really_, really_ tall man who had yet to say anything. The two men seemed suspicious, yet not outright shocked. Almost like they had heard many stranger things.

"Uh- how do you know that?" The Doctor managed to stutter out in surprise. "What are you? A Judoon with a face transplant? Raxicoricofallipatorean? Future me?"

Trench coat man (Cas, the Doctor reminded himself) looked at him with narrowed eyes, and the Doctor could almost taste the distrust in the air.

"I think the question is what are you?" The tall man (no really, he was huge) shot back, waving his gun with a warning at the Doctor.

"I'm just me. The one and only. There's no one else like me. Except for me of course, but we're not talking about them. We're talking about me."

"Just get to the point already," Dean snapped. The Doctor could see his finger tighten ever so slightly on the trigger.

"I wouldn't do that if I were you. Then we'd just get another me and that would be even more confusing for you lot." The Doctor seemed to relax slightly, and he leaned against the wall. Maybe pretending like he didn't care would make him seem more invincible.

Dean, obviously the most violent of the group, took a threatening step forward. In a heart beat, the tall guy (seriously, he had to be at least cousins with a giraffe) had snagged his gun from his hand, and pushed him back another step.

Dean staggered slightly, before glaring up at the tall guy. "Really, Sam?! Do we have to do this now?!" Dean growled.

"Yes, Dean! We don't know what he is yet! And he hasn't killed anyone yet, so we can't shoot him!" Sam (dang, how did he even find pants long enough to fit his legs?) replied.

The Doctor, suddenly thinking of all the people he _had,_ in his opinion_, _killed, or at least felt responsible for, sobered up. He figured now would not be the time to mention them anyways, since the three men seemed totally okay with shooting him.

"Yeah, see? Listen to Sam. He's a good guy," the Doctor said, almost beginning to ramble before reminding himself to shut up.

Sam glared at the Doctor for a second, and aimed his gun back at the Doctor's chest. "I wouldn't exactly say that. Now what are you?"

"I'm the Doctor."

"Doctor who?" Sam asked.

The Doctor beamed at him, shifting moods when his favorite question was brought up."Just the Doctor."

"I think the more appropriate question is 'Doctor What?'" Cas said, in his weirdly gruff voice.

"I already said once, I'm an alien!" the Doctor exclaimed. "Why is that so hard to believe? The universe is a big place, you know!"

"So why do you have a British accent?" Dean cut in.

"Because it's fun to talk in. I can do Scottish too, if you'd like. Not so sure about an American accent though, I've never been to good at those. Now Spanish - that's a fun language! Did you know, it's one of the few languages in the entire universe that rolls it's 'R's!"

"Do you ever shut up?" Dean snapped.

"Oi! You asked!"

Sam nudged Dean's shoulder with his elbow (Rassilon, the human was a tall one). Dean seemed to calm down some, and Sam handed him back his gun. Dean seemed extremely pissed at Sam, especially now that he had his gun back in his hand.

"So, are you two brothers or-?" The Doctor said, shifting forward slightly so he wasn't leaning against the wall. He glanced over trench coat guy's shoulder towards his beautiful Tardis. He reached out with his consciousness, and felt it brush against the Tardis's mind.

_Any time now, dear_, he reminded. He sensed the Tardis withdrawing from his mind, knowing that she was getting to work, preparing herself for a quick jump into the future.

Sam said, "How did you know?" At the exact moment Dean replied with "So what if we are?"

The Doctor grinned at the obvious discomfort between the two of them. Cas didn't seem fazed, he just stared at the Doctor with his head cocked to the side.

"It's quite obvious really. You two talk to each other like you've grown up together. And despite the fact that he is the size of a mountain and you are a bit on the small side-"

"Hey!" Dean interrupted.

"-you two have some physical traits that you share. Also you smell like you have lived together for a long time."

The two men frowned at each other, lowering their guns in slight disgust. Cas almost smiled. "It's true. You guys smell quite similar."

"And _why,_ have you not told me this before, Cas?" Dean said in disbelief.

Cas shrugged. "It never came up."

"And as for you, Cas," the Doctor continued, pulling out his nerdy glasses (to make him look smarter, of course) before appearing to stare at Cas critically. "I know you and Dean are a... thing?"

Cas looked stunned, but Deans mouth literally dropped open at the assumption. "We're not-"

The Doctor cut over him, continuing to address Cas. "And your not human either, although I'm not sure what you are. If you can smell that on them you are obviously a more superior species. I'm guessing your not me, since I don't hear two heartbeats. And you're not..." As the Doctor continued to ramble, he sent out another telepathic message to his Tardis. _Sometime today, girl.._. "...which means I haven't met one of you before," he concluded.

Cas only looked amused at the Doctor's guesses. Dean's mouth was still hanging open in protest, and Sam already seemed to have accepted the fact the Dean and Cas were kind of together a long time ago, and that he didn't really care one way or another.

"I'm an angel."

"Ha! You're funny, mate. Now can you tell me what you really are?"

"I'm am angel, and these two are hunters. We save people from monsters, demons, and anything supernatural."

"You mean... like ghosts?" The Doctor said, pulling out his Sonic Screwdriver and aiming it at Castiel. "Haven't met one in 907 years of roaming the universe. You're probably just handling aliens."

"Oh yeah," Dean finally found his voice again. "How do you know your not just dealing with demons and ghosts and Wendigos and so on? Aliens don't exist."

"907 years-?" Sam cut in, unsure.

The Doctor ignored him, happy to argue with Dean. He fiddled with his sonic screwdriver settings, trying to get a reading on Cas. The results were not very clear. Maybe he _was_ an angel. "Ghosts don't exist. Neither do demons. And what in the name of Rassilon is a Wendigo?"

Sam opened his mouth to say something, but at that moment the Doctor flicked his Sonic Screwdriver at the Tardis doors, which swung open with a clang. All three men (or is it one man, one giant, and one angel, the Doctor wondered) turned to face the noise, and the Doctor darted around them in a hearts-beat.

"Now, nice meeting you all but I really have to dash!" The Doctor yelled over his shoulder as he sprinted for the doors. Dean, Sam, and Cas didn't even have time to react as he made it safely through the doors, slamming them shut behind him.

The Doctor dashed to the center console, flipping one lever before smashing his left hand down on the button that would send him spinning into the time vortex.

"Thanks, dear," he said, patting the console affectionately. The Tardis beeped in response. "I'll be in the library."

Muttering under his breath, he added, "What the bloody hell is a Wendigo?"

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**Wow, my first ever crosover. This was much harder to write than I thought it would be. I have this overwhelming urge to explain why the Doctor met the Winchesters, and what time this occurred, and what season it was, and then I wanted to make a giant adventure, but then I realized it's been a while since I've posted something so i just went and wrote it. Obviously. Otherwise you wouldn't have read it. :) **

**For those of you who are following 'Just Another Story' I wrote up my chapter and when I was proofreading it my power went out so I lost everything. D: I save my documents like every five seconds now. I have to rewrite the chapter though, sorry! Thank you for your patience! :) **

**Please leave a review, and have a fantastically awesome day! :D**


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